NBC News has exclusive details of how the Pentagon could strike North Korea with B-1 bombers based in Guam, should President Trump order an attack. The targets could include two dozen missile-launch sites and other facilities, and the U.S. weapons could include a highly accurate JASSM-ER missile with a range of 500 nautical miles.

“There is no good option,” a U.S. official involved in North Korean planning told NBC News, but a U.S. bomber strike is “the best of a lot of bad options.”

For full details, watch NBC Nightly News with Lester Holt at 6:30 p.m. ET and go to nbcnews.com.